√2的整数部分为1,所以√2的小数部分M为√2-1
M^2=(√2-1)^2=2+1-2√2=3-2√2
******* 下面回答了你的问题
1/M^2=1/(3-2√2)=(3+2√2)/((3+2√2)*(3-2√2))=(3+2√2)/(9-8)=(3+2√2)
√(M^2+1/M^2-2)
=√(M^2+1/M^2-2)
=√((3-2√2)+(3+2√2)-2)
=√(3+3-2)
=√4
=2
M=(根号2)-1
M^2=3-2根号2
M^2代到式子里:
根号(M^2+1/M^2-2)
=根号[3-2根号2+1/(3-2根号2)-2]
=根号[3-2根号2+(3+2根号2)-2]
=2
(3+2根号2)=1/(3-2根号2)
你自己约啊
1<√2<2
所以m=√2-1
则1/m=√2+1
原式=√(m-1/m)²
=|m-1/m|
=|√2-1-√2-1|
=|-2|
=2